Color filter elements

Abstract

The present application relates to a kind of color filter elements, for being set in the photosensitive side of CIS detector, comprising: waveguide substrate, the waveguide substrate has a plurality of first pixel area, a plurality of second pixel area and a plurality of third pixel area periodically arranged;A plurality of first grating groups, the first grating group is set in the first pixel area;A plurality of second grating groups, the second grating group is set in the second pixel area;And a plurality of third grating groups, the third grating group is set in the third pixel area, using grating group to guide the light beam filtered by other pixel area to the detection area of CIS detector corresponding to the pixel area that can be permeated corresponding waveband, so that more the light energy of this waveband can be absorbed by CIS detector, improve the light energy use efficiency of CIS detector, to improve the sensitivity and detection quality of CIS detector.

Description

Technical Field

[0001] This invention relates to the field of optical element technology, and in particular to a color filter element. Background Technology

[0002] A CMOS image sensor (Complementary Metal-Oxide-Semiconductor Image Sensor, CIS) consists of many photosensitive units, or pixels, each of which can convert incident photons into electron charges. When light shines on the surface of the CIS detector, the semiconductor material absorbs the energy of the photons, generating electron-hole pairs. The electrons are collected in the pixel's capacitance, forming a charge accumulation proportional to the light intensity. By processing these electrical signals, an image that can be recorded and displayed can be formed.

[0003] To enable color perception in CIS detectors, a color filter array (CFA) is typically placed over each pixel's corresponding CIS detector. A common CFA array is the Bayer array, which consists of red (R), green (G), and blue (B) filters arranged in a specific pattern. The principle behind CIS detectors recording color images is as follows: different colors of light are filtered by their corresponding color filters, allowing only photons of a specific color to reach the corresponding pixel, thus enabling each pixel to respond to that specific color of light. For example, adding corresponding R, G, and B filters before R, G, and B pixels effectively blocks light in other wavelengths, allowing the CIS detector to record color images.

[0004] Because filters allow only specific wavelengths of light to pass through while reflecting other wavelengths, they filter out a large amount of light energy. This results in a significant amount of light not being received by the CIS detector, leading to a decrease in the efficiency of light energy utilization. In Bayer arrays, only one-quarter of the light energy in the R and B bands can be detected, and only half of the light energy in the G band can be detected. This causes a significant reduction in the sensitivity of the CIS detector and an increase in noise in low-light environments. Summary of the Invention

[0005] Therefore, it is necessary to provide a color filter element to address the problem of low light energy utilization efficiency in existing color perception schemes for CIS detectors.

[0006] A color filter element for use on the photosensitive side of a CIS detector, comprising:

[0007] A waveguide substrate having a plurality of first pixel regions, a plurality of second pixel regions, and a plurality of third pixel regions arranged periodically, wherein the first pixel regions correspond to a first CIS detector for detecting first band light, the second pixel regions correspond to a second CIS detector for detecting second band light, and the third pixel regions correspond to a third CIS detector for detecting third band light.

[0008] Multiple first grating groups are disposed within the first pixel area and are used to transmit first band light in the first pixel area to the first CIS detector, and to transmit second band light in the first pixel area to the second pixel area and / or to transmit third band light in the first pixel area to the third pixel area.

[0009] Multiple second grating groups, each disposed within a second pixel region, are used to transmit second-band light from the second pixel region to the second CIS detector, and to transmit first-band light from the second pixel region to the first pixel region and / or to transmit third-band light from the second pixel region to the third pixel region; and

[0010] Multiple third grating groups are disposed within the third pixel area and are used to transmit third-band light in the third pixel area to the third CIS detector, and to transmit first-band light in the third pixel area to the first pixel area and / or to transmit second-band light in the third pixel area to the second pixel area.

[0011] In some embodiments, the first grating group includes a first front-coupled-in grating disposed on the front surface of the waveguide substrate, a first rear-coupled-in grating disposed on the rear surface of the waveguide substrate, a first front-coupled-out grating disposed on the front surface of the waveguide substrate, and a first rear-coupled-out grating disposed on the rear surface of the waveguide substrate; the second grating group includes a second front-coupled-in grating disposed on the front surface of the waveguide substrate, a second rear-coupled-in grating disposed on the rear surface of the waveguide substrate, a second front-coupled-out grating disposed on the front surface of the waveguide substrate, and a second rear-coupled-out grating disposed on the rear surface of the waveguide substrate; the third grating group includes gratings disposed on the waveguide substrate... The waveguide substrate has a third front-coupled grating on its front surface, a third rear-coupled grating on its rear surface, a third front-coupled output grating on its front surface, and a third rear-coupled output grating on its rear surface, wherein the first front-coupled grating, the first rear-coupled output grating, the second front-coupled grating, the second rear-coupled output grating, the third front-coupled grating, and the third rear-coupled output grating are all transmissive gratings; and the first rear-coupled grating, the first front-coupled output grating, the second rear-coupled grating, the second front-coupled output grating, the third rear-coupled grating, and the third front-coupled output grating are all reflective gratings.

[0012] In some embodiments, the first front-coupled-in grating is disposed around the first front-coupled-out grating, and the first rear-coupled-in grating is disposed around the first rear-coupled-out grating; the second front-coupled-in grating is disposed around the second front-coupled-out grating, and the second rear-coupled-in grating is disposed around the second rear-coupled-out grating; the third front-coupled-in grating is disposed around the third front-coupled-out grating, and the third rear-coupled-in grating is disposed around the third rear-coupled-out grating.

[0013] In some embodiments, the area of ​​the first front-coupled grating is larger than the area of ​​the first front-coupled grating, and the area of ​​the first rear-coupled grating is larger than the area of ​​the first rear-coupled grating; the area of ​​the second front-coupled grating is larger than the area of ​​the second front-coupled grating, and the area of ​​the second rear-coupled grating is larger than the area of ​​the second rear-coupled grating; the area of ​​the third front-coupled grating is larger than the area of ​​the third front-coupled grating, and the area of ​​the third rear-coupled grating is larger than the area of ​​the third rear-coupled grating.

[0014] In some embodiments, the first front-coupled grating, the first rear-coupled grating, the second front-coupled grating, the second rear-coupled grating, the third front-coupled grating, and the third rear-coupled grating all have positive optical power.

[0015] In some embodiments, the first front-coupled grating, the first rear-coupled grating, the second front-coupled grating, the second rear-coupled grating, the third front-coupled grating, and the third rear-coupled grating all have negative optical power.

[0016] In some embodiments, the first grating group includes a first front diffraction grating disposed on the front surface of the waveguide substrate and / or a first rear diffraction grating disposed on the rear surface of the waveguide substrate; the second grating group includes a second front diffraction grating disposed on the front surface of the waveguide substrate and / or a second rear diffraction grating disposed on the rear surface of the waveguide substrate; the third grating group includes a third front diffraction grating disposed on the front surface of the waveguide substrate and / or a third rear diffraction grating disposed on the rear surface of the waveguide substrate.

[0017] In some embodiments, the first front diffraction grating includes two first front diffraction sub-gratings with mutually perpendicular grating vector directions, or the first rear diffraction grating includes two first rear diffraction sub-gratings with mutually perpendicular grating vector directions; the second front diffraction grating includes two second front diffraction sub-gratings with mutually perpendicular grating vector directions, or the second rear diffraction grating includes two second rear diffraction sub-gratings with mutually perpendicular grating vector directions; the third front diffraction grating includes two third front diffraction sub-gratings with mutually perpendicular grating vector directions, or the third rear diffraction grating includes two third rear diffraction sub-gratings with mutually perpendicular grating vector directions.

[0018] In some embodiments, the thickness of the waveguide substrate ranges from 0.3 mm to 3 mm.

[0019] In some embodiments, the air gap between the rear surface of the waveguide substrate and the CIS detector ranges from 1 μm to 1 mm.

[0020] The color filter element of this application utilizes a grating group to transmit second-band light from the first pixel area to the second pixel area or third-band light from the first pixel area to the third pixel area, and vice versa. This allows more first-band light to be absorbed by the first CIS detector, more second-band light to be absorbed by the second CIS detector, and more third-band light to be absorbed by the third CIS detector. This improves the light energy utilization efficiency of the CIS detector, thereby enhancing its sensitivity and detection quality. Attached Figure Description

[0021] Figure 1 A schematic diagram of the front surface of a color filter element provided in Embodiment 1 of this application;

[0022] Figure 2 A schematic diagram of the rear surface of the color filter element according to the above embodiment 1 of this application is shown;

[0023] Figure 3 As shown Figure 1 A schematic cross-sectional view of the color filter element along X1-X1 is shown.

[0024] Figure 4 A schematic diagram of the front surface of the color filter element provided in Embodiment 2 of this application;

[0025] Figure 5 A schematic diagram of the rear surface of the color filter element according to the above-described embodiment 2 of this application is shown;

[0026] Figure 6 As shown Figure 4 A schematic cross-sectional view of the color filter element along X2-X2 is shown.

[0027] Figure 7 A schematic diagram of the front surface of the color filter element provided in Embodiment 3 of this application;

[0028] Figure 8 As shown Figure 7 The diagram shows a cross-sectional view of the color filter element along X3-X3.

[0029] Reference numerals: 10, waveguide substrate; 11, first pixel region; 12, second pixel region; 13, third pixel region; 20, first grating group; 21, first front-coupled grating; 22, first rear-coupled grating; 23, first front-coupled grating; 24, first rear-coupled grating; 25, first front diffraction grating; 26, first rear diffraction grating; 30, second grating group; 31, second front-coupled grating; 32, second rear-coupled grating; 33, second front-coupled grating. 34. Second rear-coupled grating; 35. Second front diffraction grating; 36. Second rear diffraction grating; 40. Third grating group; 41. Third front-coupled grating; 42. Third rear-coupled grating; 43. Third front-coupled grating; 44. Third rear-coupled grating; 45. Third front diffraction grating; 46. Third rear diffraction grating; 50. CIS detector; 51. First CIS detector; 52. Second CIS detector; 53. Third CIS detector. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] To address the issue of low light energy utilization efficiency in existing color perception schemes for CIS detectors, a color filter element is provided. This color filter element is placed on the photosensitive side of the CIS detector and utilizes grating waveguide technology to guide light beams filtered by other pixel areas to the detection area of ​​the CIS detector corresponding to the pixel area capable of transmitting the corresponding wavelength band. This allows more light energy in that wavelength band to be absorbed by the CIS detector, improving its light energy utilization efficiency and thus enhancing its sensitivity and detection quality.

[0037] Specifically, please refer to Figure 1 , Figure 2 and Figure 3 The color filter element of this application may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30, and a plurality of third grating groups 40. The waveguide substrate 10 is periodically provided with a plurality of first pixel regions 11, a plurality of second pixel regions 12, and a plurality of third pixel regions 13. The first pixel region 11 is used to correspond to a first CIS detector 51 for detecting first wavelength light, the second pixel region 12 is used to correspond to a second CIS detector 52 for detecting second wavelength light, and the third pixel region 13 is used to correspond to a third CIS detector 53 for detecting third wavelength light. The first grating group 20 is disposed in the first pixel region 11 and is used to transmit the first wavelength light in the first pixel region 11 to the first CIS detector 51, and to transmit the second wavelength light in the first pixel region 11 to the second pixel region 12 and / or to transmit the third wavelength light in the first pixel region 11 to the third pixel region 13. The second grating group 30 is disposed within the second pixel region 12, and is used to transmit the second band light within the second pixel region 12 to the second CIS detector 52, and to transmit the first band light within the second pixel region 12 to the first pixel region 11 and / or to transmit the third band light within the second pixel region 12 to the third pixel region 13. The third grating group 40 is disposed within the third pixel region 13, and is used to transmit the third band light within the third pixel region 13 to the third CIS detector 53, and to transmit the first band light within the third pixel region 13 to the first pixel region 11 and / or to transmit the second band light within the third pixel region 13 to the second pixel region 12.

[0038] It is understandable that when the light beam illuminates the first pixel area 11 of the waveguide substrate 10, the first band of light in the beam can directly pass through the first pixel area 11 and be identified by the first CIS detector 51. Other bands of light in the beam, such as the second band light, can be transmitted by the first grating group 20 to the second pixel area 12 and emitted from the second pixel area 12 or transmitted by the second grating group 30 to the second CIS detector 52. The third band light can be transmitted by the first grating group 20 to the third pixel area 13 and emitted from the third pixel area 13 to the CIS detector 50 or transmitted by the third grating group 40 to the third CIS detector 53.

[0039] Similarly, when the light beam illuminates the second pixel area 12 of the waveguide substrate 10, the second band light in the beam can directly pass through the second pixel area 12 and be identified by the second CIS detector 52. Other band light in the beam, such as the first band light, can be transmitted by the second grating group 30 to the first pixel area 11 and emitted from the first pixel area 11 or transmitted by the first grating group 20 to the first CIS detector 51. The third band light can be transmitted by the first grating group 20 to the third pixel area 13 and emitted from the third pixel area 13 to the CIS detector 50 or transmitted by the third grating group 40 to the third CIS detector 53.

[0040] When the light beam illuminates the third pixel area 13 of the waveguide substrate 10, the third band light in the beam can directly pass through the third pixel area 13 and be identified by the third CIS detector 53. Other band light in the beam, such as the first band light, can be transmitted by the third grating group 40 to the first pixel area 11 and emitted from the first pixel area 11 or transmitted by the first grating group 20 to the first CIS detector 51. The second band light can be transmitted by the third grating group 40 to the second pixel area 12 and emitted from the second pixel area 12 to the CIS detector 50 or transmitted by the second grating group 30 to the second CIS detector 52.

[0041] In this way, by using a grating group to transmit the second-band light in the first pixel area 11 to the second pixel area 12 or the third-band light in the first pixel area 11 to the third pixel area 13, and the first-band light in the second pixel area 12 to the first pixel area 11 or the third-band light in the second pixel area 12 to the third pixel area 13, and the first-band light in the third pixel area 13 to the first pixel area 11 or the second-band light in the third pixel area 13 to the second pixel area 12, more first-band light is absorbed by the first CIS detector 51, more second-band light is absorbed by the second CIS detector 52, and more third-band light is absorbed by the third CIS detector 53. This improves the light energy utilization efficiency of the CIS detector 50, thereby enhancing the sensitivity and detection quality of the CIS detector 50.

[0042] like Figure 3 and Figure 6 As shown, in some embodiments, the first grating group 20 includes a first front-coupled-in grating 21, a first rear-coupled-out grating 24, a first front-coupled-out grating 23, and a first rear-coupled-out grating 24. The first front-coupled-in grating 21 is disposed on the front surface of the waveguide substrate 10; the first rear-coupled-in grating 22 is disposed on the rear surface of the waveguide substrate 10; the first front-coupled-out grating 23 is disposed on the front surface of the waveguide substrate 10; and the first rear-coupled-out grating 24 is disposed on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front-coupled grating 31, a second rear-coupled grating 34, a second front-coupled grating 33, and a second rear-coupled grating 34. The second front-coupled grating 31 is disposed on the front surface of the waveguide substrate 10; the second rear-coupled grating 32 is disposed on the rear surface of the waveguide substrate 10; the second front-coupled grating 33 is disposed on the front surface of the waveguide substrate 10; and the second rear-coupled grating 34 is disposed on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front-coupled grating 41, a third rear-coupled grating 44, a third front-coupled grating 43, and a third rear-coupled grating 44. The third front-coupled grating 41 is disposed on the front surface of the waveguide substrate 10; the third rear-coupled grating 42 is disposed on the rear surface of the waveguide substrate 10; the third front-coupled grating 43 is disposed on the front surface of the waveguide substrate 10; and the third rear-coupled grating 44 is disposed on the rear surface of the waveguide substrate 10. The first front-coupled grating 21, the first rear-coupled grating 24, the second front-coupled grating 31, the second rear-coupled grating 34, the third front-coupled grating 41, and the third rear-coupled grating 44 are all transmissive gratings; the first rear-coupled grating 22, the first front-coupled grating 23, the second rear-coupled grating 32, the second front-coupled grating 33, the third rear-coupled grating 42, and the third front-coupled grating 43 are all reflective gratings.

[0043] It is understood that the first front coupling grating 21, the first rear coupling grating 22, the second front coupling grating 31, the second rear coupling grating 32, the third front coupling grating 41, and the third rear coupling grating 42 can be one-dimensional gratings or two-dimensional gratings. That is, the first front coupling grating 21 and the first rear coupling grating 22 can be used to couple in one of the second or third wavelength bands of light, or simultaneously couple in both the second and third wavelength bands. The first front output grating 23 and the first rear output grating 24 can be used to couple out the first wavelength band of light. Similarly, the second front coupling grating 31 and the second rear coupling grating 32 can be used to couple in one of the first or third wavelength bands of light, or simultaneously couple in both the first and third wavelength bands. The second front output grating 33 and the second rear output grating 34 can be used to couple out the second wavelength band of light. The third front coupling grating 41 and the third rear coupling grating 42 can be used to couple in one of the first band light or the second band light, or they can be used to couple in both the first band light and the second band light at the same time. The third front coupling grating 43 and the third rear coupling grating 44 can be used to couple out the third band light.

[0044] Taking the first pixel region 11 as an example, when the light beam shines on the first pixel region 11 of the waveguide substrate 10, the first band of light in the beam can directly pass through the first pixel region 11 and be identified by the first CIS detector 51. Other bands of light in the beam, such as the second band of light, can be coupled into the waveguide substrate 10 by the first front coupling grating 21 and transmitted to the second pixel region 12 through multiple reflections of the waveguide. They are then coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the second pixel region 12. The third band of light can be coupled into the waveguide substrate 10 by the first front coupling grating 21 and transmitted to the third pixel region 13 through multiple reflections of the waveguide. They are then coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the third pixel region 13. Similarly, when the light beam illuminates the second pixel area 12 or the third pixel area 13 of the waveguide substrate 10, the first band light, the second band light and the third band light in the light beam can also be coupled out to the corresponding CIS detector 50.

[0045] like Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, in some embodiments, the first front-coupled-in grating 21 is disposed around the first front-coupled-out grating 23, and the first rear-coupled-in grating 22 is disposed around the first rear-coupled-out grating 24; the second front-coupled-in grating 31 is disposed around the second front-coupled-out grating 33, and the second rear-coupled-in grating 32 is disposed around the second rear-coupled-out grating 34; the third front-coupled-in grating 41 is disposed around the third front-coupled-out grating 43, and the third rear-coupled-in grating 42 is disposed around the third rear-coupled-out grating 44.

[0046] This configuration, by surrounding the coupling grating on the outside of the coupling grating, allows more light beams coupled into the waveguide via the coupling grating to converge to the coupling grating, reducing light energy loss and further improving the efficiency of light energy utilization.

[0047] To reduce the diffraction of incident light beams within each pixel region of the waveguide substrate 10 with the output gratings upon entering the waveguide, thereby preventing erroneous propagation of light to other pixel regions, in some embodiments, the area of ​​the first front input grating 21 is larger than that of the first front output grating 23, and the area of ​​the first rear input grating 22 is larger than that of the first rear output grating 24; the area of ​​the second front input grating 31 is larger than that of the second front output grating 33, and the area of ​​the second rear input grating 32 is larger than that of the second rear output grating 34; the area of ​​the third front input grating 41 is larger than that of the third front output grating 43, and the area of ​​the third rear input grating 42 is larger than that of the third rear output grating 44. This configuration, by setting the area of ​​the input gratings to be larger than the area of ​​the output gratings, avoids diffraction of incident light with the output gratings, reduces unnecessary light energy loss, and improves the efficiency of light energy utilization.

[0048] It is worth noting that the area of ​​the coupled-in grating in a pixel region is generally slightly smaller than the area of ​​the pixel region, and the area of ​​the coupled-out grating in a pixel region is generally no more than one-quarter of the area of ​​the pixel region.

[0049] Since the area of ​​the coupling grating is larger than the area of ​​the coupling grating, in some embodiments, to allow more light to be focused to the coupling grating, the first front coupling grating 21, the first rear coupling grating 22, the second front coupling grating 31, the second rear coupling grating 32, the third front coupling grating 41, and the third rear coupling grating 42 all have positive optical power. With this configuration, when light is coupled into the waveguide substrate 10 by the coupling grating, it can be further focused and coupled into the waveguide substrate 10. While propagating in the waveguide substrate 10, it can maintain a focused state and ultimately converge to the coupling grating, allowing more light to be transmitted to the coupling grating, thereby improving the efficiency of light energy utilization.

[0050] Since the area of ​​the output grating is smaller than that of the input grating, in order to allow the light to diffuse more evenly to the CIS detector 50 after being coupled out, in some embodiments, the first front output grating 23, the first rear output grating 24, the second front output grating 33, the second rear output grating 34, the third front output grating 43, and the third rear output grating 44 all have negative optical power. With this configuration, when light is coupled out by the output grating, its exit angle can be expanded by the output grating, thereby uniformly covering the CIS detector 50.

[0051] It is worth noting that the light transmission process of the color filter element in this application differs from that of traditional grating waveguide imaging. Therefore, it does not require strict and precise control of the beam direction; it only needs to ensure that the beam can be transmitted to the optical signal detection area of ​​the CIS detector 50 with maximum efficiency. Thus, the optical power of the grating can be designed more freely. Similarly, the pupil expansion function of traditional coupling gratings can be ignored in the color filter element of this application, minimizing the pupil expansion function to ensure that the light transmitted in the waveguide is coupled out after only one reflection.

[0052] like Figure 7 and Figure 8 As shown, in some embodiments, the first grating group 20 includes a first front diffraction grating 25 and / or a first rear diffraction grating 26, the first front diffraction grating 25 being disposed on the front surface of the waveguide substrate 10, and the first rear diffraction grating 26 being disposed on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front diffraction grating 35 and / or a second rear diffraction grating 36, the second front diffraction grating 35 being disposed on the front surface of the waveguide substrate 10, and the second rear diffraction grating 36 being disposed on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front diffraction grating 45 and / or a third rear diffraction grating 46, the third front diffraction grating 45 being disposed on the front surface of the waveguide substrate 10, and the third rear diffraction grating 46 being disposed on the rear surface of the waveguide substrate 10.

[0053] It is understood that the first front diffraction grating 25 can be used to deflect the transmission direction of the second or third band light, and the first rear diffraction grating 26 can be used to deflect the transmission direction of the second or third band light; the second front diffraction grating 35 can be used to deflect the transmission direction of the first or third band light, and the second rear diffraction grating 36 can be used to deflect the transmission direction of the first or third band light; the third front diffraction grating 45 can be used to deflect the transmission direction of the first or second band light, and the third rear diffraction grating 46 can be used to deflect the transmission direction of the first or second band light.

[0054] Taking the first pixel region 11 as an example, when a light beam illuminates the first pixel region 11 of the waveguide substrate 10, the first band of light in the beam can directly pass through the first pixel region 11 and be identified by the first CIS detector 51. Other bands of light in the beam can be transmitted to the corresponding pixel region by the first front diffraction grating 25 or the first rear diffraction grating 26. For example, the second band of light can be deflected in the transmission direction by the first front diffraction grating 25, causing the second band of light to diffract to the second pixel region 12 and be identified by the second CIS detector 52. The third band of light can be deflected in the transmission direction by the first rear diffraction grating 26, causing the third band of light to diffract to the third pixel region 13 and be identified by the third CIS detector 53. Similarly, when a light beam illuminates the second pixel region 12 or the third pixel region 13 of the waveguide substrate 10, the first band of light, the second band of light, and the third band of light in the beam can also be deflected to the corresponding CIS detector 50.

[0055] In some embodiments, the first front diffraction grating 25 includes two first front diffraction sub-gratings, the grating vector directions of the two first front diffraction sub-gratings being perpendicular to each other; or the first rear diffraction grating 26 includes two first rear diffraction sub-gratings, the grating vector directions of the two first rear diffraction sub-gratings being perpendicular to each other; the second front diffraction grating 35 includes two second front diffraction sub-gratings, the grating vector directions of the two second front diffraction sub-gratings being perpendicular to each other; or the second rear diffraction grating 36 includes two second rear diffraction sub-gratings, the grating vector directions of the two second rear diffraction sub-gratings being perpendicular to each other; the third front diffraction grating 45 includes two third front diffraction sub-gratings, the grating vector directions of the two third front diffraction sub-gratings being perpendicular to each other; or the third rear diffraction grating 46 includes two mutually perpendicular third rear diffraction sub-gratings, the grating vector directions of the two third rear diffraction sub-gratings being perpendicular to each other.

[0056] It is understood that the aforementioned front or rear diffraction grating can be a two-dimensional grating. The first front diffraction grating 25 can be used to simultaneously deflect the second-band light and the third-band light, wherein one first front diffractor grating can be used to deflect the second-band light, and the other first front diffractor grating can be used to deflect the third-band light; the first rear diffraction grating 26 can be used to simultaneously deflect the second-band light and the third-band light, wherein one first rear diffractor grating can be used to deflect the second-band light, and the other first rear diffractor grating... The grating can be used to deflect the third band light; the second front diffraction grating 35 can be used to simultaneously deflect the first band light and the third band light, wherein one second front diffraction sub-grating can be used to deflect the first band light and the other second front diffraction sub-grating can be used to deflect the third band light; the second rear diffraction grating 36 can be used to simultaneously deflect the second band light and the third band light, wherein one second rear diffraction sub-grating can be used to deflect the second band light and the other second rear diffraction sub-grating can be used to deflect the third band light.

[0057] Taking the first pixel region 11 as an example, when the light beam shines on the first pixel region 11 of the waveguide substrate 10, the first band of light in the beam can directly pass through the first pixel region 11 and be identified by the first CIS detector 51. Other bands of light in the beam can be transmitted to the corresponding pixel region by the first front diffraction grating 25 or the first rear diffraction grating 26. When the front surface of the waveguide substrate 10 is provided with the first front diffraction grating 25, the second band of light may be deflected by the first front diffraction grating to the second pixel region 12 and identified by the second CIS detector 52. The third band of light can be deflected by the first front diffraction grating to the third pixel region 13 and identified by the third CIS detector 53. When the waveguide substrate 10 has the first rear diffraction grating 26 on its rear surface, the second-band light can be deflected by the first rear diffraction grating to the second pixel area 12 and identified by the second CIS detector 52, and the third-band light can be deflected by the first rear diffraction grating to the third pixel area 13 and identified by the third CIS detector 53. Similarly, when a light beam illuminates the second pixel area 12 or the third pixel area 13 of the waveguide substrate 10, the first-band light, the second-band light, and the third-band light in the light beam can also be deflected to the corresponding CIS detector 50.

[0058] Optionally, in some embodiments, the diffraction grating can be a volume holographic grating or an embossed grating, and the grating material can be a photoresist material or a polymer material.

[0059] In some embodiments, this application does not impose a rigid requirement on the thickness of the waveguide substrate 10. The thickness of the waveguide substrate 10 can range from 0.3 mm to 3 mm. When the thickness of the waveguide substrate 10 is between 0.3 mm and 3 mm, the utilization efficiency of optical energy can be significantly improved.

[0060] Optionally, in some embodiments, the waveguide can be made of materials such as glass or resin.

[0061] Optionally, in some embodiments, in order to maintain the total reflection effect of the waveguide, the air gap between the rear surface of the waveguide substrate 10 and the CIS detector 50 can be in the range of 1 μm to 1 mm.

[0062] Optionally, in some embodiments, the first pixel region 11, the second pixel region 12, and the third pixel region 13 of the waveguide are arranged according to the Bayer array pattern. Specifically, the first pixel region 11 is an R (red) pixel region, where the first wavelength is red light; the second pixel region 12 is a G (green) pixel region, where the second wavelength is green light; and the third pixel region 13 is a B (blue) pixel region, where the third wavelength is blue light. The four adjacent pixel regions above, below, left, and right of the first pixel region 11 constitute the second pixel region 12; the two adjacent pixel regions to the left and right of the second pixel region 12 constitute the first pixel region 11; the two adjacent pixel regions above and below the second pixel region 12 constitute the third pixel region 13; and the four adjacent pixel regions above, below, left, and right of the third pixel region 13 constitute the second pixel region 12.

[0063] The color filter element of this application will be further described below with reference to specific embodiments.

[0064] Example 1

[0065] like Figure 1 , Figure 2 and Figure 3As shown, the color filter element of this embodiment may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30, and a plurality of third grating groups 40. The waveguide substrate 10 is arranged according to a Bayer array, and periodically provided with a plurality of R pixel regions, a plurality of G pixel regions, and a plurality of B pixel regions. The first grating group 20 includes a first front coupling grating 21, a first rear coupling grating 24, a first front coupling grating 23, and a first rear coupling grating 24. The first front coupling grating 21 is disposed on the front surface of the waveguide substrate 10; the first rear coupling grating 22 is disposed on the rear surface of the waveguide substrate 10; the first front coupling grating 23 is disposed on the front surface of the waveguide substrate 10; and the first rear coupling grating 24 is disposed on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front-coupled-in grating 31, a second rear-coupled-out grating 34, a second front-coupled-out grating 33, and a second rear-coupled-out grating 34. The second front-coupled-in grating 31 is disposed on the front surface of the waveguide substrate 10; the second rear-coupled-in grating 32 is disposed on the rear surface of the waveguide substrate 10; the second front-coupled-out grating 33 is disposed on the front surface of the waveguide substrate 10; and the second rear-coupled-out grating 34 is disposed on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front-coupled-in grating 41, a third rear-coupled-out grating 44, a third front-coupled-out grating 43, and a third rear-coupled-out grating 44. The third front-coupled-in grating 41 is disposed on the front surface of the waveguide substrate 10; the third rear-coupled-in grating 42 is disposed on the rear surface of the waveguide substrate 10; the third front-coupled-out grating 43 is disposed on the front surface of the waveguide substrate 10; and the third rear-coupled-out grating 44 is disposed on the rear surface of the waveguide substrate 10. Among them, the first rear-coupled grating 22, the first front-coupled grating 23, the second rear-coupled grating 32, the second front-coupled grating 33, the third rear-coupled grating 42, and the third front-coupled grating 43 are all transmissive gratings; the first rear-coupled grating 22, the first front-coupled grating 23, the second rear-coupled grating 32, the second front-coupled grating 33, the third rear-coupled grating 42, and the third front-coupled grating 43 are all reflective gratings.

[0066] The first front-out grating 23 and the first rear-out grating 24 can be used to couple out red light, the first front-in grating 21 can be used to couple in green light, and the first rear-in grating 22 can be used to couple in blue light. The second front-out grating 33 and the second rear-out grating 34 can be used to couple out green light, the second front-in grating 31 can be used to couple in red light, and the second rear-in grating 32 can be used to couple in blue light. The third front-out grating 43 and the third rear-out grating 44 can be used to couple out blue light, the third front-in grating 41 can be used to couple in red light, and the third rear-in grating 42 can be used to couple in green light. The first CIS detector 51 is used to identify red light, the second CIS detector 52 is used to identify green light, and the third CIS detector 53 is used to identify blue light.

[0067] Taking the R pixel region as an example, when the light beam illuminates the R pixel region of the waveguide substrate 10, the red light in the beam can directly pass through the R pixel region and be recognized by the first CIS detector 51. The green light in the beam can be coupled into the waveguide substrate 10 by the first front coupling grating 21, and transmitted to the G pixel region through multiple reflections of the waveguide. It is then coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the G pixel region. The blue light in the beam can be coupled into the waveguide by the first rear coupling grating 22, and transmitted to the B pixel region through multiple reflections of the waveguide. It is then coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the B pixel region. Similarly, when the light beam illuminates the G pixel region and the B pixel region of the waveguide substrate 10, the red, green, and blue light in the beam can also be coupled out to the first CIS detector 51, the second CIS detector 52, and the third CIS detector 53, respectively.

[0068] Example 2

[0069] like Figure 4 , Figure 5 and Figure 6 As shown, the color in this embodiment may include a waveguide substrate 10, multiple first grating groups 20, multiple second grating groups 30, and multiple third grating groups 40. The arrangement of the waveguide substrate 10 and grating groups in this embodiment is the same as that in Embodiment 1. The difference between Embodiment 2 and Embodiment 1 is that the first front-coupled-in grating 21, the first rear-coupled-in grating 22, the first front-coupled-out grating 23, the first rear-coupled-out grating 24, the second front-coupled-in grating 31, the second rear-coupled-in grating 32, the second front-coupled-out grating 33, the second rear-coupled-out grating 34, the third front-coupled-in grating 41, the third rear-coupled-in grating 42, and the third front-coupled-out grating 40 are arranged in the same way. Both grating 43 and the third rear-coupled grating 44 are two-dimensional gratings. The first front-coupled grating 21 and the first rear-coupled grating 22 can simultaneously couple green light and blue light, and the first front-coupled grating 23 and the first rear-coupled grating 24 can couple red light. The second front-coupled grating 31 and the second rear-coupled grating 32 can simultaneously couple red light and blue light, and the second front-coupled grating 33 and the second rear-coupled grating 34 can couple green light. The third front-coupled grating 41 and the third rear-coupled grating 42 can simultaneously couple red light and green light, and the third front-coupled grating 43 and the third rear-coupled grating 44 can couple blue light.

[0070] Taking the R pixel region as an example, when the light beam illuminates the R pixel region of the waveguide substrate 10, the red light in the beam can directly pass through the R pixel region and be identified by the first CIS detector 51. The green and blue light in the beam can be coupled into the waveguide substrate 10 by the first front coupling grating 21 or the first rear coupling grating 22, and transmitted to the G pixel region and B pixel region respectively through multiple reflections of the waveguide. Then, they are coupled out to the second CIS detector 52 by the second front coupling grating 33 or the second rear coupling grating 34 in the G pixel region, and coupled out to the third CIS detector 53 by the third front coupling grating 43 or the third rear coupling grating 44 in the B pixel region. Similarly, when the light beam illuminates the G pixel region and the B pixel region of the waveguide substrate 10, the red, green, and blue light in the beam can also be coupled out to the first CIS detector 51, the second CIS detector 52, and the third CIS detector 53 respectively.

[0071] Example 3

[0072] like Figure 7 and Figure 8 As shown, the color filter element of this embodiment may include a waveguide substrate 10, a plurality of first grating groups 20, a plurality of second grating groups 30, and a plurality of third grating groups 40. The waveguide substrate 10 is arranged in a Bayer array, with a plurality of R pixel regions, a plurality of G pixel regions, and a plurality of B pixel regions periodically. The first grating group 20 includes a first front diffraction grating 25 and a first rear diffraction grating 26. The first front diffraction grating 25 is disposed on the front surface of the waveguide substrate 10, and the first rear diffraction grating 26 is disposed on the rear surface of the waveguide substrate 10. The second grating group 30 includes a second front diffraction grating 35 and a second rear diffraction grating 36. The second grating group 30 includes a second front diffraction grating 35 disposed on the front surface of the waveguide substrate 10, and the second rear diffraction grating 36 disposed on the rear surface of the waveguide substrate 10. The third grating group 40 includes a third front diffraction grating 45 and a third rear diffraction grating 46. The third front diffraction grating 45 is disposed on the front surface of the waveguide substrate 10, and the third rear diffraction grating 46 is disposed on the rear surface of the waveguide substrate 10.

[0073] The first front diffraction grating 25 can be used to deflect the transmission direction of green light, and the first rear diffraction grating 26 can be used to deflect the transmission direction of blue light; the second front diffraction grating 35 can be used to deflect the transmission direction of red light, and the second rear diffraction grating 36 can be used to deflect the transmission direction of blue light; the third front diffraction grating 45 can be used to deflect the transmission direction of green light, and the third rear diffraction grating 46 can be used to deflect the transmission direction of red light.

[0074] When a light beam illuminates the R pixel region of the waveguide substrate 10, the red light in the beam can directly pass through the R pixel region and be detected by the first CIS detector 51. The green light in the beam may have its transmission direction deflected by the first front diffraction grating 25, causing the green light to diffract to the G pixel region and be detected by the second CIS detector 52. The blue light in the beam may have its transmission direction deflected by the first rear diffraction grating 26, causing the blue light to diffract to the B pixel region and be detected by the third CIS detector 53. When a light beam illuminates the G pixel region of the waveguide substrate 10, the green light in the beam can directly pass through the G pixel region and be detected by the second CIS detector 52. The red light in the beam may have its transmission direction deflected by the second front diffraction grating 35, causing the red light to diffract to the R pixel region and be detected by the first CIS detector 51. The blue light in the beam may have its transmission direction deflected by the second rear diffraction grating 36, causing the blue light to diffract to the B pixel region and be detected by the third CIS detector 53. When the light beam illuminates the B pixel region of the waveguide substrate 10, the blue light in the beam can directly pass through the B pixel region and be identified by the third CIS detector 53. The green light in the beam may be deflected in the transmission direction by the third front diffraction grating 45, causing the green light to diffract to the G pixel region and be identified by the second CIS detector 52. The red light in the beam may be deflected in the transmission direction by the third front diffraction grating 45, causing the red light to diffract to the R pixel region and be identified by the first CIS detector 51.

[0075] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A color filter element for use on the photosensitive side of a CIS detector, characterized in that, include: A waveguide substrate having a plurality of first pixel regions, a plurality of second pixel regions, and a plurality of third pixel regions arranged periodically, wherein the first pixel regions correspond to a first CIS detector for detecting first band light, the second pixel regions correspond to a second CIS detector for detecting second band light, and the third pixel regions correspond to a third CIS detector for detecting third band light. Multiple first grating groups are disposed within the first pixel area and are used to transmit first band light in the first pixel area to the first CIS detector, and to transmit second band light in the first pixel area to the second pixel area and / or to transmit third band light in the first pixel area to the third pixel area. Multiple second grating groups are disposed within the second pixel area to transmit second-band light in the second pixel area to the second CIS detector, and to transmit first-band light in the second pixel area to the first pixel area and / or to transmit third-band light in the second pixel area to the third pixel area; as well as Multiple third grating groups are disposed within the third pixel area and are used to transmit third-band light in the third pixel area to the third CIS detector, and to transmit first-band light in the third pixel area to the first pixel area and / or to transmit second-band light in the third pixel area to the second pixel area. The first grating group includes a first front-coupled-in grating disposed on the front surface of the waveguide substrate, a first rear-coupled-in grating disposed on the rear surface of the waveguide substrate, a first front-coupled-out grating disposed on the front surface of the waveguide substrate, and a first rear-coupled-out grating disposed on the rear surface of the waveguide substrate; the second grating group includes a second front-coupled-in grating disposed on the front surface of the waveguide substrate, a second rear-coupled-in grating disposed on the rear surface of the waveguide substrate, a second front-coupled-out grating disposed on the front surface of the waveguide substrate, and a second rear-coupled-out grating disposed on the rear surface of the waveguide substrate; the third grating group includes a first front-coupled-in grating disposed on the front surface of the waveguide substrate, a second rear-coupled-in grating disposed on the rear surface of the waveguide substrate, and a second rear-coupled-out grating disposed on the rear surface of the waveguide substrate. The waveguide substrate comprises a third front-coupled grating, a third rear-coupled grating disposed on the rear surface of the waveguide substrate, a third front-coupled output grating disposed on the front surface of the waveguide substrate, and a third rear-coupled output grating disposed on the rear surface of the waveguide substrate, wherein the first front-coupled grating, the first rear-coupled output grating, the second front-coupled grating, the second rear-coupled output grating, the third front-coupled grating, and the third rear-coupled output grating are all transmissive gratings; and the first rear-coupled grating, the first front-coupled output grating, the second rear-coupled grating, the second front-coupled output grating, the third rear-coupled grating, and the third front-coupled output grating are all reflective gratings. The first front-coupled grating, the first rear-coupled grating, the second front-coupled grating, the second rear-coupled grating, the third front-coupled grating, and the third rear-coupled grating all have positive optical power.

2. The color filter element according to claim 1, characterized in that, The first front-coupled-in grating is arranged around the first front-coupled-out grating, and the first rear-coupled-in grating is arranged around the first rear-coupled-out grating; the second front-coupled-in grating is arranged around the second front-coupled-out grating, and the second rear-coupled-in grating is arranged around the second rear-coupled-out grating; the third front-coupled-in grating is arranged around the third front-coupled-out grating, and the third rear-coupled-in grating is arranged around the third rear-coupled-out grating.

3. The color filter element according to claim 1, characterized in that, The area of ​​the first front-coupled grating is larger than that of the first front-coupled grating, and the area of ​​the first rear-coupled grating is larger than that of the first rear-coupled grating; the area of ​​the second front-coupled grating is larger than that of the second front-coupled grating, and the area of ​​the second rear-coupled grating is larger than that of the second rear-coupled grating; the area of ​​the third front-coupled grating is larger than that of the third front-coupled grating, and the area of ​​the third rear-coupled grating is larger than that of the third rear-coupled grating.

4. The color filter element according to claim 1, characterized in that, The first front-coupled grating, the first rear-coupled grating, the second front-coupled grating, the second rear-coupled grating, the third front-coupled grating, and the third rear-coupled grating all have negative optical power.

5. The color filter element according to any one of claims 1 to 4, characterized in that, The thickness of the waveguide substrate ranges from 0.3 mm to 3 mm.

6. The color filter element according to any one of claims 1 to 4, characterized in that, The air gap between the rear surface of the waveguide substrate and the CIS detector ranges from 1 μm to 1 mm.

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